Corrector circuit for synchronous telegraph systems



April 26,1932.

CORRECTOR Filed July 29, 1930 A. w. BREYFOGEL CIRCUIT FOR SYNCHRONOUS TELEGRAPH SYSTEMS 5 Sheets-Sheet l I N VEN TOR.

ATTORNEY.

April 26, 1932. A. w. BREYFOGEL 5, 8

CORRECTOR CIRCUIT FOR SYNCHRONOUS TELEGRAPH SYSTEMS Filed July 29, 1930 3 Sheet-Sheet 2 W W w n/\ AN l i I N VEN TOR.

A. WBz-eyfogeZ mam A TTORNEY.

April 26, 1932. A. w. BREYFOGEL 1,855,380

CORRECTOR CIRCUIT FOR SYNCHRONOUS TELEGRAPH SYSTEMS Filed July 29, 1930 :5 sheets sheet 3 iii rmmeaa r; 26, 1932 UNITED s'r as mam PATENT. OFFICE mum w. BBEYFOGEL, or BROOKLYN, mew Yoam'assrerroa 'ro THE wns'rmm more rmuemn com-mm, or mew YORK, 11.1, A coaroaarron' or NEW YORK i COBRECTOR CIRCUIT FOR SYNCHRONOUS TELEGRAPH SYSTEMS Application filed July 29,

This invention relates-to a corrector cir- 'cuit for use in a multiplex telegraph system for correcting the position of rotating collector brushes to maintain synchronism betwecnthe brushes at-the transmitting and receiving stations. Anobject of my invention is to devise a corrector circuit utilizing a gaseous relay of theltype commonly known as a thyratron in tube, which has the characteristic of starting into'operatjion" when a certain positive potential is applied to the grid and continuing to operate thereafter unaffected by the 1d potential. The name thyratron has en applied to tubes of this type inan ar ticle entitled Gas-filled thermionic tubes, by A. W. Hull, published in the Journal of the American Institute of Electrical Engineers, November 1928,"pag' e 802, in which 20 other forms are described.

A further object of this invention is to devisea'corrector circuit in which the number of mechanically operated contacts are reduced to a minimum.

- l5 Still another object is to devise a corrector circuit capable of operation to effect either a if forward or a backward correction of the brushes. My invention is illustrated in the accomm panying drawings in which:

Figure 1 is a circuit diagram of the corrector system;

Figure 2 is a graph of the incoming signal;

Figures 3 to 8 show graphs illustrating the operation of the corrector circuit;

Figure 9 is a circuit diagram of a modified arrangement of my corrector system; and

Fi re 10 is a detail view of the brush shifting magnet arranged for forward correcting. z'

Referring to Figure 1: L is a telegraph line or -cable circuit over which multiplextelegra h signals are received from a distant transmitting station, and A is an amplifier of usual construction for amplifying the received signals. The output circuit of the amplifier is'completed through resistance elements R and R connected in series between terminals 1 and 2. The grid of a thyratron tube T is connected to terminal I through 1830. Serial in. 471,571.

' ratron tubes are connected together and to the midpoint of resistances R and R and t6 the negative terminal of plate battery B. The

plate elements of tubes T and T are connect- I ed together through resistance elements B, and R connected in series between terminals 3 and 4; Space current is supplied to the plate elements of the tubes by a connection from the positive terminal of battery B to the midpoint connection between resistance elements B and R. A condenser C is connected in shunt to the terminals 3 and 4. The output circuit of the thyratron tubes T and T includes a transformer TR connected across terminals 3 and 4 by means of a network including condensers C and C resistances R and- R and an indu'ctance 5.' The secondary of transformer TB is connected at one terminal to the solid corrector ring and at the other terminal to the cathode of a corrector thyratron tube T The grid of tube T is connected to the segments of the corrector ring CR through a suitable stabilizing battery and high resistance element. The grid. is also connected to the cathode of the tube T through a suitable stabilizing battery and a high resistance. The cathode of an auxiliary corrector thyratron tube T is connected to the cathode of tube T and to the negative terminal of battery B. Space current for tubes T and T are supplied from battery B by a connection 16 through resistance elements R and R respectively, which are shunted by a condenser C the plate circuit of tube T including a corrector magnet M. The grid of tube T is connected to its cathode element through a' suitable stabilizing battery and a high resistance, and is also connected through a high resistance to a stationary contact 6, cooperating with an insulated contact 7, carried by the armature 8, of the corrector magnet -M, contact 7 being connected to the conductor leading to the plate element of tube T The armature 8 carries a pawl 9 cooperating with I a ratchet wheel 10 which has suitable well a stabilizin battery and a high resistanceknown mec anical connection with the ropose the brushes at the correcting station are set to run slightly slower than tating brush structure of the rotary distri' those at the sending station, and the butor for shifting the brushes while in operation. The arm 8 is normally biased by spring 11 against the operation of magnet M.

The operation is as follows: The incoming signal is represented by the graph in Figure 2. When the signal wave is such that terminal 1 ,becomes positive, and terminal 2 becomes negative operation of thyratron tube T is initiated and current flows from battery B through resistance R and the plate circuit of tube T Under this condition the volta e of terminal 3 connected to the plate of tu e T and to one terminal of condenser C will be of the order of 15 volts, corresponding to the internal drop in tube T The other terminal of condenser 0 that is, terminal 4, will assume the full voltage of battery B (assume 115 volts) by reason of the connections through resistance R...

Should the signal now reverse in polarity, making terminal 2 positive and terminal 1 negative, operation of tube T will be initiated, and the voltage of terminal 4 will immediately drop from 115 voltsto 15 volts.- The voltage of terminal 3 must also instantaneously decrease by the same amount, which will bring it to minus 85 volts, from which it will rise gradually to plus 115 volts as the condenser C is discharged and then again charged through resistance-R This change of voltage at terminal 3, or at the plate of tube T is of such duration as to permit the ions to diffuse to the electrodes and stop the operation of tube T When the signal again causes terminal 1 to become positive and terminal 2 to become negative, the same operation described above with respect to the tube 2 takes place with respect to tube 1.

The variation of potential across terminals 3 and 4 for signal currents represented in Figure 2 is shown in the graph in Figure 3.

The instantaneous voltage changes across condenser C when impressed upon the input of transformer TR through its associated network, results in voltage kicks in the secondary of the transformer as shown in the graph in Figure 4. These kicks rise very rapidly to their maximum value and fall back to zero equally as rapidly. They are positive when the incoming signal changes from negative to positive, and negative when"= the signal changes from positive to negative. The voltage kicks or impulses are supplied from transformer TR to the grid circuit of corrector tube T The brushes of the rotary distributor at the correcting station are set torun either slightly faster or slightly slower than the brushes of the distributor at the sending station, and the mechanical corrector is arranged to step the brushes either backward or forward in the well known manner. Sup- 7 open.

mechanical corrector 1s arranged to step the brushes forward. When the corrector brushes are in correct phase relation with the incoming signal, their position with respect to the segments 12 of the corrector, and with respect to the kicks from the secondary side of transformer T will be somewhat as shown in Fig. 5. As the brushes 14 are gradually brought back onto the corrector segment, a condition such as shown in Figure 6 will be reached, in which the grid circuit of the corrector tube T is completed through the corrector brush on the corrector segment at the same instant that the pulse is produced in the'secondary circuit.

The auxiliary corrector tube'T is normally energized, maintaining the corrector magnet M energized, thereby holding the armature 8 attracted and keeping contacts 6 and Condenser C. is normally charged from battery B through resistance R,. When a signalimpulse causes the grid of 90 tube T to become positive at the same time that the brush completes a circuit through a live segment on the corrector ring, the corrector tube begins to operate, causing its plate element to drop in potential form 115 volts to 15 volts, and-through the action of condenser C4, stopping the operation of the tube T The armature 8 is moved away from the magnet core by the action of spring 11, thereby moving the ratchet wheel 10 one tooth and applying the correction to the rotating brushes. When the armature 8 completes its released stroke, contacts 6 and 7 complete the circuit from the plate element T to its grid element, applying a positive potential to the 105 grid of tube T thereby starting operation of this tube, and through the action of the condenser C stopping the operation of tube T The corrector magnet remains energized until the next correcting operation 110 takes place. In adapting this system for backward correction of the distributor brushes, the correction is applied on the energizing stroke of the corrector magnet.

In Fig. 9 I have shown a slight modifica- 115 tion of the corrector circuit in which the contacts 6 and 7 are eliminated. The receiving circuit is the same as in Fig. 1, the changes being confined to the circuit connected with the secondary of transformer TR.

The operation will be evident from the pre vious description of Fig. 1. The auxiliary corrector tube T, is normally operating, but

stant that the corrector brush 14 engages a segment 12 of the segmented ring of the corrector distributor, thereby causing the.

explain-ed, through the action of the condenser 0,, stops the operation of tube T The brush corrector magnet M is in the plate circuit of the tube T and is therefore energized, the current flowing from the plus pole of battery B through conductor 16, resistance R magnet M. anode and cathode of tube T back to the negative pole of B battery. As its armature 8 moves toward the magnet core, the pawl 9 pushes the ratchet 10 forward one notch, thereby shifting the brushes backwardly a small amount and bringing them into exact phase relation with the incoming signal impulses. In this modification I have utilized the changing flux in the magnet to bring about the starting of the tube T. and the stopping of the tube T in the following manner:

The current in the coil of the magnet first rises, then falls and again rises in the manner indicated in the graph shown in Fig. 7. At the point 7a, the current has risen sufiicicntly to cause the armature 8 to move toward the magnet. As the armature approaches the core, the flux increases rapidly and produces a counter electromotive force which induces an E. M. F. opposing the battery. thus causing the current in the coil to decrease to a value indicated at 71), when the armature strikes the core. The current then again increases and reaches a value dependent upon the constants of the circuit. This change in the current value produces a cor responding change in the voltage drop across the resistance R which is impressed through the action of the condenser 0., upon the primary of the transformer TR and causes a sharp voltage kick in the transformer sec ondary, as indicated in the graph shown in Fig. 8. These kicks produced in the secondary circuit rise very rapidly to their maximum value and return to zero with equal rapidity. They are negative when the current starts to flow through the magnet coil and positive when the current decreases due to the influence of the moving armature.

These voltage kicks in the secondary of the transformer "TR are applied to the grid circuit of the thyratron tube T The kick of positive polarity causes the tube T to start, resulting in a drop of potential at the plate or anode from 115 volts to 15 volts, and through the action of the condenser C stops the operation of the tube T The magnet M is thus deenergized and its armature is pulled to its back stop by the spring 11'.

WVhen the distributor brushes at the correcting station are driven slightly slower than those at the sending or transmitting station the corrector is arranged to step the brushes forward at each'correction. In that case the armature of the corrector magnet may be connected to the pawl and ratchet in the brush shifting device in the manner i11- dicatcd in Fig. 10.

From the foregoing it will be seen that I have devised a corrector system in which two relays of the thyratron tube type are arranged to repeat the positive and negative impulses into the corrector circuit, and means is provided for deenergizing one relay upon the energization of the other. It Wlll also be seen that I employ thyratronrelays in the corrector circuit proper for controlling the corrector magnet to apply the correction to rotating brushes, thereby reducing to a'minimum the number of circuit contacts required in the system, as in Fig. 1, or eliminating contacts entirely as in the arrangements disclosed in Figs. 9 and 10.

I claim:

1. In a telegraph signaling system, the combination of a telegraph line, a pair of impedance elements connected in series across the terminals of said line, a pair of thyratron relays having their grid elements connected respectively to the terminals of said line, and their cathodes connected together and to the midpoint of said impedance elements, a circuit connection between the plate elements of said relays including two impedance elements in series, a source of space current connected between the cathodes of said relays and the midpoint of said last mentioned impedance elements, a condenser connected between the platcs of said relays, and an output circuit including a condenser and a transformer connected in series across the terminals of said condenser.

2. In a telegraph corrector circuit the combination of a pair of corrector rings, a thyratron relay having a grid circuit completed through said corrector rings and including means for supplying correcting impulses from a telegraph line, means connected in the plate circuit of said relay for applying a correction to the rotating brush of said corrector rings, and means actuated by said correction applying means for deenergizing said thyratron relay.

3. In a telegraph corrector system, the combination of a pair of corrector rings including a'rotating brush, means for applying a correction to said brush, means tending normally to apply a correction, means including a normally energized thyratron relay for opposing said second means, a second thyratron relay having a grid circuit completed through the corrector rings and including means for supplying correcting signal impulses, and means connected in the output circuit of said second relay responsive to the energization of the plate circuit thereof to deenergize the first relay upon the closing of the grid circuit of the second relay throughsaid corrector rings simultaneously with the occurrence of a correcting impulse.

4. In a telegraph corrector system,the combination of a pair of corrector rings including a rotating brush, means for ap lying a correction to said brush, means ten ing normally to apply a correction, means including a normally energized thyratron relay for 011- posing said second means, a second thymtron relay having -a grid circuit completed through the corrector rings and including means for supplying correcting signal impulses, means connected in the output. circuit of said second relay responsive to the energization of the plate circuit thereof to deenergize the first relay upon the closing of the grid circuit of the second relay through said corrector rings simultaneously with the occurrence of a correcting impulse, and means actuated by operation of said correction applyingmeans to deenergize said second relay.

In testimony whereof I afiix my signature.

ALBERT W. BREYFOGEL. 

